- 1 Cycle: - 1 ____ and 1 ____ - The start of a ____ to the start of the next ____

- 1 Cycle: - 1 Compression and 1 Rarefaction - The start of a cycle to the start of the next cycle

Period - Definition— Period is the ____ it takes a wave to ____ a single ____, or the time from the start of one ____ to the start of the next ____ - Units— Period is reported in units of ____, such as ____ (µs), seconds, hours, or days - Typical values— The typical value of period in diagnostic ultrasound is ____ to ____ ____ (µs) - This may also be written as: - 6 x 10⁻⁸ to 5 x 10⁻⁷ seconds - 0.06 to 0.5 µs - 0.000 000 06 to 0.000 000 5 seconds - Determined by— Period is determined by the ____ only, not by the ____ - Adjustable— ____. The sonographer ____ change the period while using a basic ultrasound system with a particular transducer - Formula— ____

Period - Definition— Period is the time it takes a wave to vibrate a single cycle, or the time from the start of one cycle to the start of the next cycle - Units— Period is reported in units of time, such as microseconds (µs), seconds, hours, or days - Typical values— The typical value of period in diagnostic ultrasound is 0.06 to 0.5 microseconds (µs) - This may also be written as: - 6 x 10⁻⁸ to 5 x 10⁻⁷ seconds - 0.06 to 0.5 µs - 0.000 000 06 to 0.000 000 5 seconds - Determined by— Period is determined by the sound source only, not by the medium - Adjustable— No. The sonographer cannot change the period while using a basic ultrasound system with a particular transducer - Formula— P = 1/f

Frequency - Definition— Frequency is the ____ of particular events that occur in a specific duration of time - For example, the frequency of presidential elections in the United States is 25 times per century - The frequency of the menstrual cycle is 12 times per year - In diagnostic sonography, the frequency of a wave is described as the number of ____ that occurs in ____ ____ - Units— Frequency is reported in units ____ ____ , 1/second, ____ (Hz) - Hertz is another way to say “____ ____ ” - 1 cycle/second = 1 hertz - 1,000 cycles/second = ____ ____ - 1,000,000 cycles/second = ____ ____ - Typical values— In clinical imaging, frequency ranges from approximately ____ ____ to ____ ____ - Another way to say this is ____ ____ to ____ ____ per ____ - Determined by— Frequency of a sound wave is determined by the ____ only, not by the ____ through which the sound is traveling - Adjustable— ____ . The sonographer ____ change the frequency while using a basic ultrasound system and transducer - Formula— ____

Frequency - Definition— Frequency is the number of particular events that occur in a specific duration of time - For example, the frequency of presidential elections in the United States is 25 times per century - The frequency of the menstrual cycle is 12 times per year - In diagnostic sonography, the frequency of a wave is described as the number of cycles that occurs in one second - Units— Frequency is reported in units per second, 1/second, Hertz (Hz) - Hertz is another way to say “per second” - 1 cycle/second = 1 hertz - 1,000 cycles/second = 1 kHz - 1,000,000 cycles/second = 1 MHz - Typical values— In clinical imaging, frequency ranges from approximately 2 MHz to 15 MHz - Another way to say this is 2 million to 15 million per seconds - Determined by— Frequency of a sound wave is determined by the sound source only, not by the medium through which the sound is traveling - Adjustable— No. The sonographer cannot change the frequency while using a basic ultrasound system and transducer - Formula— F = 1/P

How did ultrasound get its name? - ____ is classified based on the ability of humans to hear it - If the ____ of a sound wave is less than ____ Hz, it is below the threshold of human hearing and cannot be heard - That is, the sound is ____ - Sound waves with frequencies this low are defined as infrasonic or ____ - Humans can hear sound with frequencies between ____ Hz and ____ Hz - This is called ____ - Sound with frequencies so high that humans ____ hear it is called ultrasonic or ____ - Ultrasound’s frequency is higher than ____ Hz (____ kHz)

How did ultrasound get its name? - Sound is classified based on the ability of humans to hear it - If the frequency of a sound wave is less than 20 Hz, it is below the threshold of human hearing and cannot be heard - That is, the sound is inaudible - Sound waves with frequencies this low are defined as infrasonic or infrasound - Humans can hear sound with frequencies between 20 Hz and 20,000 Hz - This is called audible - Sound with frequencies so high that humans cannot hear it is called ultrasonic or ultrasound - Ultrasound’s frequency is higher than 20,000 Hz (20 kHz)

Why is frequency important in diagnostic sonography? - Frequency is important in sonography because it affects ____ and ____ ____ - [Penetration— ____ ____] - [Image quality— ____ ____] - As frequency increases, penetration is ____, and image quality/detail is ____ - As frequency decreases, penetration is ____ ____, and image quality/detail is ____

- Frequency is important in sonography because it affects penetration and image quality - [Penetration— How deep] - [Image quality— Image resolution] - As frequency increases, penetration is deeper, and image quality/detail is higher - As frequency decreases, penetration is more shallow, and image quality/detail is less

What is the Relationship between Frequency and Period? - Period and frequency are ____ ____ to each other - As frequency ____, period decreases - As frequency decreases, period ____ - If one of these parameters remains constant, then the other remains ____ - Period and frequency have an even more special relationship that is called ____ - When two reciprocal parameters are multiplied together, the result is ____ - Period x Frequency = ____ - (The ____ it takes a wave to ____ a single cycle) x (the ____ of cycles that occurs in ____ second) = 1 - Use complimentary units: - Seconds and ____ - ____ and kilohertz

What is the Relationship between Frequency and Period? - Period and frequency are inversely related to each other - As frequency increases, period decreases - As frequency decreases, period increases - If one of these parameters remains constant, then the other remains unchanged - Period and frequency have an even more special relationship that is called reciprocal - When two reciprocal parameters are multiplied together, the result is 1 - Period x Frequency = 1 - (The time it takes a wave to vibrate a single cycle) x (the of cycles that occurs in 1 second) = 1 - Use complimentary units: - Seconds and hertz - Milliseconds and kilohertz

More about Hertz - Frequency is reported with units of ____ - Some people believe that hertz means “____ ____ ____” - (1) Hertz means events per second - (2) To which event are we referring? - For example, what is the meaning of a sound wave with a frequency of 100 Hz? - (1) 100 events occur each second - (2) A cycle is our event. In this case, 100 Hz means 100 ____ per second - What is the meaning of a flat-screen TV with a frame rate of 120 Hz? - (1) 120 events occur each second - (2) A frame is our event. Thus, the TV displays 120 frames per second - What is the meaning of an individual with a heart rate of 1 Hz? - (1) One event occurs each second - (2) A heartbeat is the event. The individual’s heart contracts at a rate of 1 beat per second (or 60 beats per minute)

More about Hertz - Frequency is reported with units of hertz (Hz) - Some people believe that hertz means “cycles per second” - (1) Hertz means events per second - (2) To which event are we referring? - For example, what is the meaning of a sound wave with a frequency of 100 Hz? - (1) 100 events occur each second - (2) A cycle is our event. In this case, 100 Hz means 100 cycles per second - What is the meaning of a flat-screen TV with a frame rate of 120 Hz? - (1) 120 events occur each second - (2) A frame is our event. Thus, the TV displays 120 frames per second - What is the meaning of an individual with a heart rate of 1 Hz? - (1) One event occurs each second - (2) A heartbeat is the event. The individual’s heart contracts at a rate of 1 beat per second (or 60 beats per minute)

Three “Bigness” Parameters - Three parameters describe the size, ____, or ____ of a sound wave: - (1) - (2) - (3)

Three “Bigness” Parameters - Three parameters describe the size, magnitude, or strength of a sound wave: - (1) Amplitude - (2) Power - (3) Intensity

Amplitude - Definition— Amplitude is the “____” of a wave - It is the difference between the ____ value and the ____ or ____ value of an acoustic variable - Amplitude is also the difference between minimum value and the ____ value of the ____ variable - Units— Amplitude can have units of any of the ____ ____ - Amplitude, in relative terms, can also be expressed in ____ (____) - Typical values— In clinical imaging, pressure amplitude ranges from ____ ____ pascals (____) to ____ ____ pascals (____) - Determined by— Initially, amplitude is determined only by the ____, the ultrasound system - However, amplitude decreases as sound propagates through the body - The rate at which amplitude decreases as sound propagates depends on the characteristics of both the sound wave and the medium - Adjustable— ____. A control system on a basic ultrasound system allows the sonographer to ____ initial amplitude of a wave - Formula—

Amplitude - Definition— Amplitude is the “bigness” of a wave - It is the difference between the maximum value and the average or undisturbed value of an acoustic variable - Amplitude is also the difference between minimum value and the average value of the acoustic variable - Units— Amplitude can have units of any of the acoustic variables - Amplitude, in relative terms, can also be expressed in decibels (dB) - Typical values— In clinical imaging, pressure amplitude ranges from 1 million pascals (1 MPa) to 3 million pascals (3 MPa) - Determined by— Initially, amplitude is determined only by the sound source, the ultrasound system - However, amplitude decreases as sound propagates through the body - The rate at which amplitude decreases as sound propagates depends on the characteristics of both the sound wave and the medium - Adjustable— Yes. A control system on a basic ultrasound system allows the sonographer to alter initial amplitude of a wave - Formula—

What is the difference between amplitude and peak-to-peak amplitude? - Amplitude is measured from the ____, or undisturbed, value to the ____ - Peak-to-peak amplitude is the ____ between ____ and ____ values of an acoustic variable - Therefore, peak-to-peak amplitude is ____ the value of the amplitude

What is the difference between amplitude and peak-to-peak amplitude? - Amplitude is measured from the middle, or undisturbed, value to the maximum - Peak-to-peak amplitude is the difference between maximum and minimum values of an acoustic variable - Therefore, peak-to-peak amplitude is twice the value of the amplitude

Power - Definition— Power is the ____ of energy ____ or the ____ at which ____ is performed - Power, like ____, and ____, describes the “____” of a wave - Units— Power have the unit of ____ - Typical values— In clinical imaging, typical powers range from ____ to ____ watts (____ to ____ milliwatts), depending on the diagnostic ultrasound technique - Determined by— Just like amplitude, initial power is determined by the ____, the ultrasound system - Power ____ as sound propagates through the body - The rate at which power ____ as sound propagates depends on the characteristics of the medium and the wave - Adjustable— ____. Initial power, like amplitude, ____ be changed. A control on the ultrasound systems allows the sonographer to ____ the initial power of a wave - Formula— ____

Power - Definition— Power is the rate of energy transfer or the rate at which work is performed - Power, like amplitude, and intensity, describes the “bigness” of a wave - Units— Power have the unit of watts - Typical values— In clinical imaging, typical powers range from 0.004 to 0.090 watts (4 to 90 milliwatts), depending on the diagnostic ultrasound technique - Determined by— Just like amplitude, initial power is determined by the sound source, the ultrasound system - Power decreases as sound propagates through the body - The rate at which power decreases as sound propagates depends on the characteristics of the medium and the wave - Adjustable— Yes. Initial power, like amplitude, can be changed. A control on the ultrasound systems allows the sonographer to alter the initial power of a wave - Formula— Power ∝ Amplitude²

How are amplitude and power related? - Both amplitude and power are parameters that describe ____, or ____, of a wave - When power increases, ____ ____ amplitude - Similarly, when power decreases, amplitude ____ - Mathematically, power is ____ to the wave’s amplitude ____, The term is multiplied by itself - Power ∝ Amplitude² - [The symbol ∝ means proportional to]

How are amplitude and power related? - Both amplitude and power are parameters that describe size, or magnitude, of a wave - When power increases, so does amplitude - Similarly, when power decreases, amplitude decreases - Mathematically, power is proportional to the wave’s amplitude squared, The term is multiplied by itself - Power ∝ Amplitude² - [The symbol ∝ means proportional to]

Intensity - Definition— Intensity is the ____ of energy in a sound beam - To calculate intensity, divide the beam’s ____ by the beam’s ____-____ ____ - Intensity, like ____ and ____, describes the “____” of a wave - Intensity relates to how the power in a wave ____ or is____ in space - Therefore, intensity depends on both the ____ in the beam and the ____ over which the power is applied - Units— The units of intensity are____/____ centimeter, or (____) (watts from ___ and ____ from beam area) - Typical values— In clinical imaging, intensity ranges from ____ to ____ ____ - Determined by— Just like ____ and____, initial intensity is determined only by the ____, the ultrasound system - Intensity changes as sound propagates through the body - The ____ at which intensity changes as sound propagates depends on the characteristics of both the sound wave and the medium - Adjustable—____. Initial intensity, like____ and____, ____ be changed - A control on a basic ultrasound systems allows the sonographer to ____ the initial intensity of a wave - Formula— ____

Intensity - Definition— Intensity is the concentration of energy in a sound beam - To calculate intensity, divide the beam’s power by the beam’s cross-sectional area - Intensity, like power and amplitude, describes the “bigness” of a wave - Intensity relates to how the power in a wave spreads or is distributed in space - Therefore, intensity depends on both the power in the beam and the area over which the power is applied - Units— The units of intensity are watts/square centimeter, or W/cm² (watts from power and cm² from beam area) - Typical values— In clinical imaging, intensity ranges from 0.01 to 300 W/cm² - Determined by— Just like amplitude and power, initial intensity is determined only by the sound source, the ultrasound system - Intensity changes as sound propagates through the body - The rate at which intensity changes as sound propagates depends on the characteristics of both the sound wave and the medium - Adjustable— Yes. Initial intensity, like power and amplitude, can be changed - A control on a basic ultrasound systems allows the sonographer to alter the initial intensity of a wave - Formula— I = P/A

More About Intensity - ____, ____, and intensity are three ____ that describe the ____ or strength of a ____ - These parameters tend to be____ related; Therefore, when intensity____, power and amplitude also____

More About Intensity - Amplitude, power, and intensity are three parameters that describe the magnitude or strength of a wave - These parameters tend to be directly related; Therefore, when intensity increases, power and amplitude also increase

How is intensity related to power and amplitude? - When discussing relationships between amplitude, power, and intensity, the word squared always follows the word ____ - Power is related to the amplitude ____ - Intensity is related to the ____ squared - Power is related to the ____

How is intensity related to power and amplitude? - When discussing relationships between amplitude, power, and intensity, the word squared always follows the word amplitude - Power is related to the amplitude squared - Intensity is related to the amplitude squared - Power is related to the intensity

Relationship between Intensity and Power - Mathematically, intensity is ____ to power - Intensity ∝ Power - Examples: - When a wave’s power is____, the intensity is doubled - When a wave’s power is quartered, the intensity is ____

Relationship between Intensity and Power - Mathematically, intensity is proportional to power - Intensity ∝ Power - Examples: - When a wave’s power is doubled, the intensity is doubled - When a wave’s power is quartered, the intensity is quartered

Ch. 3: Describing Sound Waves Flashcards by Nancy Nguyen

Parameters describe features of a ____ ____

Parameters describe features of a sound wave

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The values of seven parameters are required to completely characterize a ____ ____

The values of seven parameters are required to completely characterize a sound wave

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The ____ of a sound wave is the ultrasound system and ____

The source of a sound wave is the ultrasound system and transducer

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Some parameters are determined by the ____ through which the ____ is traveling; The tissue is also called the ____

Some parameters are determined by the tissue through which the sound is traveling; The tissue is also called the medium

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Features of a sound wave:

Definition
- Units
- Typical values
- Determined/established by
- Adjustable
- Formula/concept

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1 Cycle:
- 1 ____ and 1 ____
- The start of a ____ to the start of the next ____

1 Cycle:
- 1 Compression and 1 Rarefaction
- The start of a cycle to the start of the next cycle

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Period

Definition— Period is the ____ it takes a wave to ____ a single ____, or the time from the start of one ____ to the start of the next ____
Units— Period is reported in units of ____, such as ____ (µs), seconds, hours, or days
Typical values— The typical value of period in diagnostic ultrasound is ____ to ____ ____ (µs)
- This may also be written as:
  - 6 x 10⁻⁸ to 5 x 10⁻⁷ seconds
  - 0.06 to 0.5 µs
  - 0.000 000 06 to 0.000 000 5 seconds
Determined by— Period is determined by the ____ only, not by the ____
Adjustable— ____. The sonographer ____ change the period while using a basic ultrasound system with a particular transducer
Formula— ____

Period

Definition— Period is the time it takes a wave to vibrate a single cycle, or the time from the start of one cycle to the start of the next cycle
Units— Period is reported in units of time, such as microseconds (µs), seconds, hours, or days
Typical values— The typical value of period in diagnostic ultrasound is 0.06 to 0.5 microseconds (µs)
- This may also be written as:
  - 6 x 10⁻⁸ to 5 x 10⁻⁷ seconds
  - 0.06 to 0.5 µs
  - 0.000 000 06 to 0.000 000 5 seconds
Determined by— Period is determined by the sound source only, not by the medium
Adjustable— No. The sonographer cannot change the period while using a basic ultrasound system with a particular transducer
Formula— P = 1/f

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Frequency

Definition— Frequency is the ____ of particular events that occur in a specific duration of time
- For example, the frequency of presidential elections in the United States is 25 times per century
  - The frequency of the menstrual cycle is 12 times per year
- In diagnostic sonography, the frequency of a wave is described as the number of ____ that occurs in ____ ____
Units— Frequency is reported in units ____ ____ , 1/second, ____ (Hz)
- Hertz is another way to say “____ ____ ”
- 1 cycle/second = 1 hertz
- 1,000 cycles/second = ____ ____
- 1,000,000 cycles/second = ____ ____
Typical values— In clinical imaging, frequency ranges from approximately ____ ____ to ____ ____
- Another way to say this is ____ ____ to ____ ____ per ____
Determined by— Frequency of a sound wave is determined by the ____ only, not by the ____ through which the sound is traveling
Adjustable— ____ . The sonographer ____ change the frequency while using a basic ultrasound system and transducer
Formula— ____

Frequency

Definition— Frequency is the number of particular events that occur in a specific duration of time
- For example, the frequency of presidential elections in the United States is 25 times per century
  - The frequency of the menstrual cycle is 12 times per year
- In diagnostic sonography, the frequency of a wave is described as the number of cycles that occurs in one second
Units— Frequency is reported in units per second, 1/second, Hertz (Hz)
- Hertz is another way to say “per second”
- 1 cycle/second = 1 hertz
- 1,000 cycles/second = 1 kHz
- 1,000,000 cycles/second = 1 MHz
Typical values— In clinical imaging, frequency ranges from approximately 2 MHz to 15 MHz
- Another way to say this is 2 million to 15 million per seconds
Determined by— Frequency of a sound wave is determined by the sound source only, not by the medium through which the sound is traveling
Adjustable— No. The sonographer cannot change the frequency while using a basic ultrasound system and transducer
Formula— F = 1/P

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Frequency of infrasound:

Less than 20 Hz/0.02 kHz

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Frequency of audible sound:

Between 20 Hz/0.02 kHz and 20,000 Hz/20 kHz

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Frequency of ultrasound:

Greater than 20,000 Hz/20 kHz

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How did ultrasound get its name?

____ is classified based on the ability of humans to hear it
If the ____ of a sound wave is less than ____ Hz, it is below the threshold of human hearing and cannot be heard
That is, the sound is ____
Sound waves with frequencies this low are defined as infrasonic or ____
Humans can hear sound with frequencies between ____ Hz and ____ Hz
This is called ____
Sound with frequencies so high that humans ____ hear it is called ultrasonic or ____
Ultrasound’s frequency is higher than ____ Hz (____ kHz)

How did ultrasound get its name?

Sound is classified based on the ability of humans to hear it
If the frequency of a sound wave is less than 20 Hz, it is below the threshold of human hearing and cannot be heard
That is, the sound is inaudible
Sound waves with frequencies this low are defined as infrasonic or infrasound
Humans can hear sound with frequencies between 20 Hz and 20,000 Hz
This is called audible
Sound with frequencies so high that humans cannot hear it is called ultrasonic or ultrasound
Ultrasound’s frequency is higher than 20,000 Hz (20 kHz)

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Why is frequency important in diagnostic sonography?

Frequency is important in sonography because it affects ____ and ____ ____
[Penetration— ____ ____]
[Image quality— ____ ____]
As frequency increases, penetration is ____, and image quality/detail is ____
As frequency decreases, penetration is ____ ____, and image quality/detail is ____

Frequency is important in sonography because it affects penetration and image quality
[Penetration— How deep]
[Image quality— Image resolution]
As frequency increases, penetration is deeper, and image quality/detail is higher
As frequency decreases, penetration is more shallow, and image quality/detail is less

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What is the Relationship between Frequency and Period?

Period and frequency are ____ ____ to each other
As frequency ____, period decreases
As frequency decreases, period ____
If one of these parameters remains constant, then the other remains ____
Period and frequency have an even more special relationship that is called ____
When two reciprocal parameters are multiplied together, the result is ____
- Period x Frequency = ____
- (The ____ it takes a wave to ____ a single cycle) x (the ____ of cycles that occurs in ____ second) = 1
Use complimentary units:
- Seconds and ____
- ____ and kilohertz

What is the Relationship between Frequency and Period?

Period and frequency are inversely related to each other
As frequency increases, period decreases
As frequency decreases, period increases
If one of these parameters remains constant, then the other remains unchanged
Period and frequency have an even more special relationship that is called reciprocal
When two reciprocal parameters are multiplied together, the result is 1
- Period x Frequency = 1
- (The time it takes a wave to vibrate a single cycle) x (the # of cycles that occurs in 1 second) = 1
Use complimentary units:
- Seconds and hertz
- Milliseconds and kilohertz

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More about Hertz

Frequency is reported with units of ____
Some people believe that hertz means “____ ____ ____”
- (1) Hertz means events per second
- (2) To which event are we referring?
For example, what is the meaning of a sound wave with a frequency of 100 Hz?
- (1) 100 events occur each second
- (2) A cycle is our event. In this case, 100 Hz means 100 ____ per second
What is the meaning of a flat-screen TV with a frame rate of 120 Hz?
- (1) 120 events occur each second
- (2) A frame is our event. Thus, the TV displays 120 frames per second
What is the meaning of an individual with a heart rate of 1 Hz?
- (1) One event occurs each second
- (2) A heartbeat is the event. The individual’s heart contracts at a rate of 1 beat per second (or 60 beats per minute)

More about Hertz

Frequency is reported with units of hertz (Hz)
Some people believe that hertz means “cycles per second”
- (1) Hertz means events per second
- (2) To which event are we referring?
For example, what is the meaning of a sound wave with a frequency of 100 Hz?
- (1) 100 events occur each second
- (2) A cycle is our event. In this case, 100 Hz means 100 cycles per second
What is the meaning of a flat-screen TV with a frame rate of 120 Hz?
- (1) 120 events occur each second
- (2) A frame is our event. Thus, the TV displays 120 frames per second
What is the meaning of an individual with a heart rate of 1 Hz?
- (1) One event occurs each second
- (2) A heartbeat is the event. The individual’s heart contracts at a rate of 1 beat per second (or 60 beats per minute)

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Three “Bigness” Parameters

Three parameters describe the size, ____, or ____ of a sound wave:
- (1)
- (2)
- (3)

Three “Bigness” Parameters

Three parameters describe the size, magnitude, or strength of a sound wave:
- (1) Amplitude
- (2) Power
- (3) Intensity

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Amplitude

Definition— Amplitude is the “____” of a wave
- It is the difference between the ____ value and the ____ or ____ value of an acoustic variable
- Amplitude is also the difference between minimum value and the ____ value of the ____ variable
Units— Amplitude can have units of any of the ____ ____
- Amplitude, in relative terms, can also be expressed in ____ (____)
Typical values— In clinical imaging, pressure amplitude ranges from ____ ____ pascals (____) to ____ ____ pascals (____)
Determined by— Initially, amplitude is determined only by the ____, the ultrasound system
- However, amplitude decreases as sound propagates through the body
- The rate at which amplitude decreases as sound propagates depends on the characteristics of both the sound wave and the medium
Adjustable— ____. A control system on a basic ultrasound system allows the sonographer to ____ initial amplitude of a wave
Formula—

Amplitude

Definition— Amplitude is the “bigness” of a wave
- It is the difference between the maximum value and the average or undisturbed value of an acoustic variable
- Amplitude is also the difference between minimum value and the average value of the acoustic variable
Units— Amplitude can have units of any of the acoustic variables
- Amplitude, in relative terms, can also be expressed in decibels (dB)
Typical values— In clinical imaging, pressure amplitude ranges from 1 million pascals (1 MPa) to 3 million pascals (3 MPa)
Determined by— Initially, amplitude is determined only by the sound source, the ultrasound system
- However, amplitude decreases as sound propagates through the body
- The rate at which amplitude decreases as sound propagates depends on the characteristics of both the sound wave and the medium
Adjustable— Yes. A control system on a basic ultrasound system allows the sonographer to alter initial amplitude of a wave
Formula—

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What is the difference between amplitude and peak-to-peak amplitude?

Amplitude is measured from the ____, or undisturbed, value to the ____
Peak-to-peak amplitude is the ____ between ____ and ____ values of an acoustic variable
- Therefore, peak-to-peak amplitude is ____ the value of the amplitude

What is the difference between amplitude and peak-to-peak amplitude?

Amplitude is measured from the middle, or undisturbed, value to the maximum
Peak-to-peak amplitude is the difference between maximum and minimum values of an acoustic variable
- Therefore, peak-to-peak amplitude is twice the value of the amplitude

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Power

Definition— Power is the ____ of energy ____ or the ____ at which ____ is performed
- Power, like ____, and ____, describes the “____” of a wave
Units— Power have the unit of ____
Typical values— In clinical imaging, typical powers range from ____ to ____ watts (____ to ____ milliwatts), depending on the diagnostic ultrasound technique
Determined by— Just like amplitude, initial power is determined by the ____, the ultrasound system
- Power ____ as sound propagates through the body
- The rate at which power ____ as sound propagates depends on the characteristics of the medium and the wave
Adjustable— ____. Initial power, like amplitude, ____ be changed. A control on the ultrasound systems allows the sonographer to ____ the initial power of a wave
Formula— ____

Power

Definition— Power is the rate of energy transfer or the rate at which work is performed
- Power, like amplitude, and intensity, describes the “bigness” of a wave
Units— Power have the unit of watts
Typical values— In clinical imaging, typical powers range from 0.004 to 0.090 watts (4 to 90 milliwatts), depending on the diagnostic ultrasound technique
Determined by— Just like amplitude, initial power is determined by the sound source, the ultrasound system
- Power decreases as sound propagates through the body
- The rate at which power decreases as sound propagates depends on the characteristics of the medium and the wave
Adjustable— Yes. Initial power, like amplitude, can be changed. A control on the ultrasound systems allows the sonographer to alter the initial power of a wave
Formula— Power ∝ Amplitude²

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How are amplitude and power related?

Both amplitude and power are parameters that describe ____, or ____, of a wave
When power increases, ____ ____ amplitude
Similarly, when power decreases, amplitude ____
Mathematically, power is ____ to the wave’s amplitude ____, The term is multiplied by itself
Power ∝ Amplitude²
[The symbol ∝ means proportional to]

How are amplitude and power related?

Both amplitude and power are parameters that describe size, or magnitude, of a wave
When power increases, so does amplitude
Similarly, when power decreases, amplitude decreases
Mathematically, power is proportional to the wave’s amplitude squared, The term is multiplied by itself
Power ∝ Amplitude²
[The symbol ∝ means proportional to]

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Intensity

Definition— Intensity is the ____ of energy in a sound beam
- To calculate intensity, divide the beam’s ____ by the beam’s ____-____ ____
Intensity, like ____ and ____, describes the “____” of a wave
- Intensity relates to how the power in a wave ____ or is____ in space
- Therefore, intensity depends on both the ____ in the beam and the ____ over which the power is applied
Units— The units of intensity are____/____ centimeter, or (____) (watts from ___ and ____ from beam area)
Typical values— In clinical imaging, intensity ranges from ____ to ____ ____
Determined by— Just like ____ and____, initial intensity is determined only by the ____, the ultrasound system
- Intensity changes as sound propagates through the body
- The ____ at which intensity changes as sound propagates depends on the characteristics of both the sound wave and the medium
Adjustable—____. Initial intensity, like____ and____, ____ be changed
- A control on a basic ultrasound systems allows the sonographer to ____ the initial intensity of a wave
Formula— ____

Intensity

Definition— Intensity is the concentration of energy in a sound beam
- To calculate intensity, divide the beam’s power by the beam’s cross-sectional area
- Intensity, like power and amplitude, describes the “bigness” of a wave
- Intensity relates to how the power in a wave spreads or is distributed in space
- Therefore, intensity depends on both the power in the beam and the area over which the power is applied
Units— The units of intensity are watts/square centimeter, or W/cm² (watts from power and cm² from beam area)
Typical values— In clinical imaging, intensity ranges from 0.01 to 300 W/cm²
Determined by— Just like amplitude and power, initial intensity is determined only by the sound source, the ultrasound system
- Intensity changes as sound propagates through the body
- The rate at which intensity changes as sound propagates depends on the characteristics of both the sound wave and the medium
Adjustable— Yes. Initial intensity, like power and amplitude, can be changed
- A control on a basic ultrasound systems allows the sonographer to alter the initial intensity of a wave
Formula— I = P/A

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More About Intensity

____, ____, and intensity are three ____ that describe the ____ or strength of a ____
These parameters tend to be____ related; Therefore, when intensity____, power and amplitude also____

More About Intensity

Amplitude, power, and intensity are three parameters that describe the magnitude or strength of a wave
These parameters tend to be directly related; Therefore, when intensity increases, power and amplitude also increase

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How is intensity related to power and amplitude?

When discussing relationships between amplitude, power, and intensity, the word squared always follows the word ____
- Power is related to the amplitude ____
- Intensity is related to the ____ squared
- Power is related to the ____

How is intensity related to power and amplitude?

When discussing relationships between amplitude, power, and intensity, the word squared always follows the word amplitude
- Power is related to the amplitude squared
- Intensity is related to the amplitude squared
- Power is related to the intensity

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Relationship between Intensity and Power

Mathematically, intensity is ____ to power
Intensity ∝ Power
Examples:
- When a wave’s power is____, the intensity is doubled
- When a wave’s power is quartered, the intensity is ____

Relationship between Intensity and Power

Mathematically, intensity is proportional to power
Intensity ∝ Power
Examples:
- When a wave’s power is doubled, the intensity is doubled
- When a wave’s power is quartered, the intensity is quartered

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**Relationship between Intensity and Amplitude** - Mathematically, intensity is ____ to the wave’s ____ squared - The term “squared” means that a number is multiplied by itself - Intensity **∝** Amplitude² - Examples: - When a wave’s amplitude is doubled, the intensity increases to ____ times its original value

**Relationship between Intensity and Amplitude** - Mathematically, intensity is proportional to the wave’s amplitude squared - The term “squared” means that a number is multiplied by itself - Intensity **∝** Amplitude² - Examples: - When a wave’s amplitude is doubled, the intensity increases to four times its original value

**Wavelength** - **Definition—** Wavelength is the ____ or ____ of ____ complete cycle - For example, imagine a sound wave as similar to a train; Wavelength is the length of a single boxcar in a train - **Units—** Wavelength is measured in units of mm, meters, or any other unit of ____ - **Typical values—** In clinical imaging, wavelength in soft tissues ranges from ____ to ____ ____ - **Determined by—** Wavelength is determined by **____*** - Wavelength is the ____ parameter that is determined by ____ - Wavelength is speed ____ by frequency - Speed is determined by the ____ and is ____ - Frequency is determined by the ____ - **Adjustable—**____. The wavelength ____ be changed by the sonographer when using a basic ultrasound transducer - **Formula—** ____ - λ— ____ or ____ - c— ____ - f— ____

**Wavelength** - **Definition—** Wavelength is the distance or length of one complete cycle - For example, imagine a sound wave as similar to a train; Wavelength is the length of a single boxcar in a train - **Units—** Wavelength is measured in units of mm, meters, or any other unit of length - **Typical values—** In clinical imaging, wavelength in soft tissues ranges from 0.1 to 0.8 mm - **Determined by—** Wavelength is determined by **both the source and the medium*** - Wavelength is the only parameter that is determined by both - Wavelength is speed divided by frequency - Speed is determined by the medium and is constant - Frequency is determined by the source - **Adjustable—** No. The wavelength cannot be changed by the sonographer when using a basic ultrasound transducer - **Formula—** λ = c/f - λ— lamba or wavelength - c— speed - f— frequency

**What is the difference between wavelength and period?** - Both wavelength and period describe a ____ cycle in a sound wave - Wavelength refers to the ____ or ____ of a ____ ____ - Period refers to the ____ that it takes to complete a ____ ____ - Wavelength and period are differentiated by their ____ ; Wavelength has units of ____ , whereas period has units of ____

**What is the difference between wavelength and period?** - Both wavelength and period describe a single cycle in a sound wave - Wavelength refers to the length or distance of a single cycle - Period refers to the time that it takes to complete a single cycle - Wavelength and period are differentiated by their units; Wavelength has units of distance, whereas period has units of time

**What is the relationship between wavelength and frequency?** - As long as a wave remains in one ____, wavelength and frequency are ____ related - As frequency increases, wavelength ____ - The lower the frequency, the ____ the wavelength

**What is the relationship between wavelength and frequency?** - As long as a wave remains in one medium, wavelength and frequency are inversely related - As frequency increases, wavelength decreases - The lower the frequency, the longer the wavelength

**What is the wavelength of 1 MHz sound in soft tissue?** - In soft tissue, sound with a frequency of ____ ____ has a wavelength of ____ ____

**What is the wavelength of 1 MHz sound in soft tissue?** - In soft tissue, sound with a frequency of 1 MHz has a wavelength of 1.54 mm

**What is the rule that defines the relationship between frequency and wavelength of sound in soft tissues?** - To find the wavelength of a sound wave in soft tissue, divide ____ ____ by the frequency in ____: - wavelength (mm) = (____ ____/____) **/** ( frequency--____)

**What is the rule that defines the relationship between frequency and wavelength of sound in soft tissues?** - To find the wavelength of a sound wave in soft tissue, divide 1.54 mm by the frequency in MHz: - wavelength (mm) = (1.54 mm/µs) **/** ( frequency--MHz)

**Why is wavelength important in diagnostic ultrasound?** - Wavelength plays a very important role in ____ ____ - Shorter wavelengths are created by ____ frequency sound, This usually produces ____ quality images with ____ detail - Sonographers should try to use ____ frequency transducers rather than ____ frequency transducers

**Why is wavelength important in diagnostic ultrasound?** - Wavelength plays a very important role in image quality - Shorter wavelengths are created by high frequency sound, This usually produces higher quality images with greater detail - Sonographers should try to use higher frequency transducers rather than lower frequency transducers

**Propagation Speed** - **Definition—** Propagation speed is the ____ at which a sound wave travels through a ____ - **Units—** Speed is measured in units of ____ per ___, ____/µs, or any ____ divided by ____ - **Typical values—** In the body, the speed of sound ranges from ____ ____/____ to ____ ____/____, **depending on the tissue** through which it is traveling - **Determined by—** Speed is determined only by the **____** through which the sound is traveling - Speed is not affected by the nature of the sound wave - All sound, regardless of the frequency, travels at the same speed through any specific medium - This means that sound with a frequency of 5 MHz and sound with a frequency of 3 MHz travel at the ____ propagation speed in the ____ medium - **Adjustable—**____. Speed of sound ____ be changed by the sonographer - Speed ____ ____ when the wave travels from one medium to a different medium - Speed is ____ in any given medium - **Formula—** speed (m/s) = ____

**Propagation Speed** - **Definition—** Propagation speed is the rate at which a sound wave travels through a medium - **Units—** Speed is measured in units of meters per second, mm/µs, or any distance divided by time - **Typical values—** In the body, the speed of sound ranges from 500 m/s to 4000 m/s, **depending on the tissue** through which it is traveling - **Determined by—** Speed is determined only by the **medium** through which the sound is traveling - Speed is not affected by the nature of the sound wave - All sound, regardless of the frequency, travels at the same speed through any specific medium - This means that sound with a frequency of 5 MHz and sound with a frequency of 3 MHz travel at the same propagation speed in the same medium - **Adjustable—** No. Speed of sound cannot be changed by the sonographer - Speed changes only when the wave travels from one medium to a different medium - Speed is constant in any given medium - **Formula—** speed (m/s) = frequency (Hz) x wavelength (m)

**What is the speed of sound in soft tissue?** - ____ m/s - ____ mm/µs - ____ km

**What is the speed of sound in soft tissue?** - 1,540 m/s - 1.54 mm/µs - 1.54 km

**What is the speed of sound in biologic tissues other than soft tissue?** - Lung - Fat - Soft Tissue (average) - Liver - Blood - Muscle - Tendon - Solid bone

**What is the speed of sound in biologic tissues other than soft tissue?** - Lung-- 500 - Fat-- 1,450 - Soft Tissue (average)-- 1,540 - Liver-- 1,560 - Blood-- 1,560 - Muscle-- 1,600 - Tendon-- 1,700 (1,850) - Solid bone-- 2,000 - 4,800

**What are the biologic tissues other than soft tissue from slow to fast?**

- Lung - Fat - Soft Tissue - Liver - Blood - Muscle - Tendon - Solid bone

**What are the biologic tissues other than soft tissue from fast to slow ?**

- Solid bone - Tendon - Muscle - Blood - Liver - Soft Tissue - Fat - Lung

**What is the speed of sound in other media?** - As a general rule, sound travels fastest in ____, slower in ____, and ____ in gases - Solids have more particles, it is more ____

**What is the speed of sound in other media?** - As a general rule, sound travels fastest in solids, slower in liquids, and slowest in gases - Solids have more particles, it is more dense

**What is the speed of sound in air?**

SPEED (m/s) 330

**What is the speed of sound in water?**

SPEED (m/s) 1,480

**What is the speed of sound in metals?**

SPEED (m/s) 2,000 - 7,000

**What characteristics of a medium determine the speed of sound in that medium?** - Two characteristics of a medium affect the speed of sound: - (1) - (2)

**What characteristics of a medium determine the speed of sound in that medium?** - Two characteristics of a medium affect the speed of sound: - (1) Stiffness - (2) Density

**Stiffness** - Stiffness describes the ability of an object to resist ____ - A stiff material will ____ its shape, whereas a non-stiff material will ____ its shape - How does stiffness affect speed? - Stiffness and speed are ____ related - The speed of sound will be ____ in the ____ medium - What other terms describe stiffness? **____ ____** is the ____ as stiffness - **____** and **____** are the opposite of stiff - A marshmallow may be described as not ____, a ____ bulk modulus, ____ elastic, or highly ____

**Stiffness** - Stiffness describes the ability of an object to resist compression - A stiff material will retain its shape, whereas a non-stiff material will change its shape - How does stiffness affect speed? - Stiffness and speed are directly related - The speed of sound will be higher in the stiffer medium - What other terms describe stiffness? **Bulk modulus** is the same as stiffness - **Elasticity** and **compressibility** are the opposite of stiff - A marshmallow may be described as not stiff, a low bulk modulus, highly elastic, or highly compressible

**Density** - Density describes the ____ ____ of a material - When ____ volumes of two materials are compared, the dense material weighs ____ ____, whereas the non-dense material weighs ____ - How does density affect speed? - Density and speed are ____ related - As materials become more dense (heavier), the speed of sound in the material ____ - Sound travels faster in media with ____ density - If two media are equally stiff, the ____ medium will have a ____ speed

**Density** - Density describes the relative weight of a material - When equal volumes of two materials are compared, the dense material weighs a lot, whereas the non-dense material weighs little - How does density affect speed? - Density and speed are inversely related - As materials become more dense (heavier), the speed of sound in the material decreases - Sound travels faster in media with low density - If two media are equally stiff, the denser medium will have a lower speed

Period: (Definition)

The time it takes a wave to vibrate a single cycle, or the time from the start of one cycle to the start of the next cycle

Period: (Units)

Time, such as microseconds (µs), seconds, hours, or days

Period: (Typical values)

0.06 to 0.5 microseconds (µs)

Period: (Determined by)

sound source

Period: (Adjustable)

Period: (Formula)

P = 1/f

Frequency: (Definition)

The number of cycles that occurs in one second

Frequency: (Units)

Units per second, 1/second, hertz, Hz

Frequency: (Typical values)

2 MHz to 15 MHz

Frequency: (Determined by)

sound source

Frequency: (Adjustable)

Frequency: (Formula)

F = 1/P

Amplitude: (Definition)

The difference between the maximum value and the average; The difference between minimum value and the average

Amplitude: (Units)

pascals (Pa), kg/cm³, cm, dB

Amplitude: (Typical values)

1 million pascals (1 MPa) to 3 million pascals (3 MPa)

Amplitude: (Determined by)

sound source

Amplitude: (Adjustable)

Yes

Amplitude: (Formula)

Power: (Definition)

The rate of energy transfer or the rate at which work is performed

Power: (Units)

watts

Power: (Typical values)

0.004 to 0.090 watts (4 to 90 milliwatts)

Power: (Determined by)

sound source

Power: (Adjustable)

Yes

Power: (Formula)

Power ∝ Amplitude²

Intensity: (Definition)

The concentration of energy in a sound beam

Intensity: (Units)

watts/square centimeter, or W/cm² (watts from power and cm² from beam area)

Intensity: (Typical values)

0.01 to 300 W/cm²

Intensity: (Determined by)

sound source

Intensity: (Adjustable)

Yes

Intensity: (Formula)

I = P/A

Wavelength: (Definition)

The distance or length of one complete cycle

Wavelength: (Units)

mm, meters, or any other unit of length

Wavelength: (Typical values)

0.1 to 0.8 mm

Wavelength: (Determined by)

both the source and the medium

Wavelength: (Adjustable)

Wavelength: (Formula)

λ = c/f

Propagation speed: (Defintion)

The rate at which a sound wave travels through a medium

Propagation speed: (Units)

meters per second, mm/µs, or any distance divided by time

Propagation speed: (Typical values)

500 m/s to 4000 m/s

Propagation speed: (Determined by)

medium

Propagation speed: (Adjustable)

Propagation speed: (Formula)

speed (m/s) = frequency (Hz) x wavelength (m)

Relation Between: Frequency and Period

Inversely

Relation Between: Amplitude and Power

Directly

Relation Between: Amplitude and Intensity

Directly

Relation Between: Power and Intensity

Directly

Relation Between: Wavelength and Intensity

Unrelated

Relation Between: Wavelength and Frequency

Inversely

Relation Between: Acoustic velocity and Density

Inversely

Relation Between: Elasticity and Speed of sound

Inversely

Relation Between: Acoustic velocity and Compressibility

Inversely

Relation Between: Stiffness and sound speed

Directly

Relation Between: Frequency and Sound speed

Unrelated

Relation Between: Frequency and Intensity

Unrelated

Relation Between: Power and Frequency

Unrelated